IgG4関連進行性線維化間質性肺疾患患者における水素吸入後の制御性T細胞増加およびFas陽性T細胞サブセット減少：症例報告
An 85-year-old female with suspected IgG4-related progressive fibrosing interstitial lung disease (PF-ILD) complicated by hospital-acquired pneumonia received molecular hydrogen inhalation. By the fourth day, chest X-ray imaging revealed a reduction in pulmonary infiltrations, and the patient began progressing toward mechanical ventilation weaning. Immune phenotyping conducted before and after hydrogen exposure showed a marked elevation in resting regulatory T cell (Treg) counts alongside a substantial decline in Fas-positive helper T cell and cytotoxic T cell subsets. These immunological shifts suggest that molecular hydrogen may modulate immune responses in PF-ILD through anti-inflammatory and antioxidant mechanisms, warranting further investigation in larger patient cohorts.
Molecular hydrogen is proposed to exert anti-inflammatory and antioxidant effects that upregulate resting regulatory T cells while downregulating Fas-positive helper and cytotoxic T cell subsets, thereby modulating immune-mediated pulmonary fibrosis.
For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.
See also:
https://h2-papers.org/en/papers/38688598